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TECH UPDATE: Skidders


Tech Update Editor: Mel-Lynda Andersen
Copyright 1997. Contact publisher for permission to use.

Caterpillar

Caterpillar brings three skidder models to the market for 1997. The Cat 525 is reported to offer a 12 to 14 per-cent productivity improvement over its predecessor, the Cat 518C. One of the most noticeable improvements, says the company, is the new operator compartment; the new design is 35 per cent roomier than the former cab and there is 72 per cent more window area to the side and rear. A steering wheel, which replaces the tiller bar of the former model, ensures single-hand tractor control. Transmission controls for forward, reverse and first through fourth gears are located at the operator's fingertips.

Cat's Auto-grab Hydraulics features constant tong pressure, eliminating the need for grapple accumulators. The pressure-sensing system only activates the pump when needed, reports Caterpillar.

OSB The Cat Monitoring System (CMS), a three-level monitoring system, oversees a variety of machine functions and includes a diagnostic feature that, when plugged into a special service tool, reports problems such as temperature spikes and recent alert messages. Maintenance-free inboard brakes use hydraulic activation, eliminating the need for an air compressor and air dryer. Instead of frame oscillation, the new tractor relies on front axle cradle oscillation, improving tractor stability with large grapples. The Cat 525 is available with several log-handling arrangements, which means up to 120''/3,048 mm grapples can be used. Also new is a four-speed power-shift transmission, providing one more working gear than the former model.The Cat 3304 Direct Injection Turbocharged diesel engine is rated at 160 hp/119.4 kW.

Smaller and narrower than the Cat 525, the new Cat 515 features new grapple and tire options for improved productivity. A four-position joystick control with two rocker switches commands grapple operation through a low-pressure pilot valve. Cat Auto-grab Hydraulics is also standard on the 515. The Cat 515 is available only with a single-function grapple arch. The wheel base is 130''/3,300 mm, a full 8''/203 mm shorter than the Cat 525, helping match the needs and requirements of smaller production capacity logging operations. The new Cat 515 skidder utilizes the Cat 3304 Direct Injection, Turbocharge diesel engine rated at 140 hp/104.4 kW.

The Caterpillar 527 track skidder features the Caterpillar elevated sprocket drive system and extended track roller frame for optimum balance and a torque converter drivetrain for high drawbar pull. The 150-hp skidder is available in both cable and grapple arrangements. Features include long track roller frame with an extension to the rear; an elevated sprocket design and proven D6R undercarriage which increases ground clearance; an extended track which increases flotation for improved performance in tough underfoot conditions; and powershift transmission and single lever control of the blade, easing operation, reports the company. John Deere Upgrading its popular E-series line of skidders, Deere & Company's recently introduced G-series line features improvements such as continuous 360 grapple head rotation, new equipment frames and larger fuel tank capacity. Included in the G-series are the 548G and 648G single-function grapple skidders and the 540G, 640G and 740G cable skidders; the 648G and 748G dual-function grapple skidders and the 748G single-function grapple skidder will be available soon.

OSB All G-series grapple skidders have continuous 360 grapple head rotation. The grapple arch and head design have been redesigned with the rotate motor and rotary manifold located in the upper end of the arch assembly. The G-series grapple rotate motor generates twice the torque available on the E-series, says the company.

The new grapple head features dual cylinders for increased log clamping and independent tong movement. The 648's clamping force has increased 50 per cent as compared to the 648E; the 548G has a 36 per-cent increase in clamping force of the 548E, the company reports. A flow divider assembly is used to time the movement of the two independent tong cylinders; this allows the tongs to conform to the shape of the load. Once logs are clamped by the tongs, the flow divider prevents hydraulic oil backflow from the cylinders and locks the tongs in position.

The G-series also features a new single-function grapple arch on the 548G and the 648G to accommodate the new grapple head assemblies. The new arch uses box section construction for reduced weight, increased durability and reliability, says Deere. Hydraulic hoses for grapple rotate and tong functions are now fully protected, having been routed through box sections in the arch and equipment frame assemblies. Equipment frames have been redesigned to accommodate the new style of grapple assemblies, and the fuel tank capacity has been increased on all grapple skidders. The 548G has a 50-gallon tank; the 648G (single function) has a 70-gallon tank; and the 648G (dual function), and the 748G (single function and dual function) have 72-gallon tanks.

Other changes include increased engine horsepower on the 640G and 648G, from 140 to 150 hp; increased tong-to-tip opening on the 548G single-function grapple, from 75'' to 85''; new log arch for cable skidders, including stronger support for the vertical rollers, better roller pin retention, and stronger support; and new, stronger cable and grapple fenders.

Timberjack

With eight models to choose from, Timberjack's new line of 60-series skidders has been completely redesigned, with the end goal of bringing more wood to the roadside at a lower cost, according to the manufacturer. The pulling power of the 60-series skidders is the result of a redistribution of weight to the front end, giving the machines the balance to lift and skid heavier loads; plus a power to weight ratio and tractive effort developed by the high torque rise engine; and the six-speed close-ratio "smart" transmission, providing precise gear selection in the working range to match conditions, says Timberjack.

The 3,000-psi, closed-centre hydraulic system gives simultaneous power on demand and increased speeds to all hydraulic functions as well as constant grapple tong pressure. New cylinder rod seals and electrical connectors, as well as extended winch drive shaft life and improved frame pivot design are among some of the features that have improved the reliability of these machines, says the company. And as an assist in preventative maintenance, there is an electronic monitor for on-board diagnostics.

Tigercat

The manufacturers of the Tigercat 630 hydrostatic skidder have produced a high-performance all-terrain skidder, the Tigercat 630. Shifting transmission controls are now obsolete with Tigercat's hydrostatic drive, says the company - a simple touch of the foot control and the machine is in motion. Pilot-operated controls facilitate grappling and constant pressure grapple hydraulics will not let go of the load. OSB

Specifications include 127'' width, 124'' height, 24.5'' ground clearance, Cummins 6CT8.3 engine, 86-US-gallon fuel capacity, inboard planetary axles (front 15 oscillating), independent differential locks in front and rear, hydrostatic dynamic braking system, and enclosed oil-cooled secondary brakes. Esco 100'' sorting grapple is standard,with 90'' to 120'' bunching grapples as options.

Silvitech Industries The Morgan skidder from Int. Silvatech, utilizing a Detroit-Perkins 210-hp and its newly developed Synchro-Trac hydraulic drive system, accomplishes unsurpassed traction control, claims the manufacturer. The Synchro-Trac system controls each wheel independently, synchronizing wheel speed in relation to the machine's steering geometry, facilitating speeds under a full load. As the inside wheel slows down and the outside wheel speeds up through a turn, Synchro-Trac infinitely adjusts the full-time differential lock-up. All equipment functions are controlled by left and right joysticks mounted to a 180 swivel seat, providing additional comfort while operating the 120'' dual-function grapple and skidding blade with the right joystick, and simultaneously controlling all steering and propel functions with the left joystick. The steering system combines independent or integrated steering of the forward axle, an articulated frame and a rear axle, providing an inside turning radius of 15', crabbing capabilities, as well as unlimited maneuverability in tight spots, says the company.

Allied Systems

Allied Systems Company has introduced a new H-series skidder featuring pressurized cab, differential lock and a larger transmission. The new Ranger H66, H66DS and H67 skidders will replace the current F66, F66DS and F67 skidders. The new isolated cab is pressurized to keep the noise and dust out. A steering wheel with quick steering is now standard equipment. A differential lock axle is also now standard on the rear, and optional on the front. It features on-the-go lock-up at the flip of a switch, says the company. A new Clark 32,000-series transmission is now standard on the 177-hp H67.

OSB According to the manufacturer, among other improvements built into the new H66-H67 skidders are standard power-assist brakes to enhance operator productivity; standard hydraulic oil cooler so that hydraulic components run cooler and last longer; a larger-capacity hydraulic pump with higher operating pressure to increase the speed of hydraulic operations and boost grapple gripping power; and a 24V - 70-amp electrical system that more than doubles the previous capacity rating to support the power demands of the air conditioner/heater and lighting in a 24-hour operation.

Based at Portland, Oregon, Allied manufactures a series of wood-handling equipment which includes the Ranger skidders, Wagner log stackers and chip dozers, tree harvesters, cranes, as well as logging winches acquired from Hyster Company several years ago. Allied has also recently acquired the Hanover line of forwarders and harvesters.

KMC

Kootenay Manufacturing Co. Ltd. has introduced the KMC Hydrostatic Drive Track skidders, the only true hydrostatic drive track skidder in the industry, according to the manufacturer. KMC's torsion bar-sprung suspension, live steel track and balanced weight distribution are some of the features of the KMC track skidders, which are capable of working on steep slopes, on wet and boggy ground or in sensitive soils while causing a reduced level of site degradation.

OSB Driven by Cummins 6BTA5.9 (177-hp) engines, these new skidders are also equipped with Sunstrand 90-series hydraulic drive motors, Sunstrand 45-series load-sensing hydraulic accessory drive pumps and pilot hydraulic systems. Variable speed and power are available to either track at all times, thus completing power to both tracks during turns both forward and reverse as well as providing the ability to counter rotate.

Ergonomic changes include a fully enclosed, sound-suppressed ROPS/ Operator compartment, swivel suspension seat with joystick controls, hydraulic steering assist with dual or single joystick controls, illuminated and raised instrument panel for improved access and readability, and a cab- and boom-mounted quartz outside lighting system with 360 night visibility.


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